Non-destructive testing (NDT) is used extensively across a range of industries to evaluate the properties of a test object without causing damage to the test object. Examples of test objects include composite aircraft panels, gas-turbine engine components, pipelines and pressure vessels.
It is known to integrate an NDT sensor into a test object in order to provide, for example, reliable repeatable measurement and/or in situ monitoring while the test object is in service. For example, it is known to integrate an ultrasonic sensor in or on a test object.
Performing measurements using an integrated NDT sensor can however be challenging due to the difficulty associated with making wired connections to an integrated NDT sensor. One option for addressing this problem is to provide an integrated NDT sensor with its own power storage device, but this can result in a bulky sensor. Moreover, recharging or replacing the power storage device can be difficult if the integrated sensor is inaccessible; for example, if the sensor is partially or fully embedded within the test object.
It is therefore known to provide wireless integrated NDT sensors that can be inductively coupled to an external measurement device. The inductive coupling enables power to be provided to the integrated sensor from the external device in a similar manner to known radio-frequency identification (RFID) modules. The inductive coupling can also be used for the transfer of measurement information from the integrated sensor back to the external device.
However, the present inventors have identified that known wireless NDT sensors can be large, heavy and/or overly complex in design.